Gas cooktop appliance



FIG. 1 is a top perspective view of a gas cooktop appliance, showing my new design;

FIG. 2 is side elevational view thereof; and,

FIG. 3 is an end elevational view thereof.

The portion shown in broken lines in FIGS. 1-3 is shown for illustrative purposes only and forms no part of the claimed design. The undisclosed bottom is flat and unornamented. 

The ornamental design for a gas cooking appliance, as shown and described. 